In U.S. Pat. No. 3,788,527 issued July 30, 1974 there is disclosed a quick release aerator that stores a large volume of gas under significant pressure and then releases the gas into a storage vessel, producing a blast of gas which dislodges stuck or bridged material to be unloaded from the vessel. While this device is quite effective in dislodging and loosening clogged and/or bridged lading, it often requires a plurality of such aerators to be mounted on the vessel so that gas discharged from the aerators reaches into most, if not all parts of the vessel. Thus in many instances a number of aerators are required for each vessel to be unloaded.
In U.S. Pat. No. 3,958,722 a self indexing elbow discharge device is disclosed which may be utilized with a source of high pressure gas such as an accumulator and discharge valve means for timed release of this pressurized gas. The self indexing elbow rotates upon discharge of a blast of gas from the discharge end of the elbow so that after several discharges a large volume of the storage vessel comes under action of the blast. Thus through the use of the self indexing elbow described in U.S. Pat. No. 3,958,722 fewer discharge valves, discharge devices and associated conduits are required to dislodge bridged and/or clogged lading.
However, a problem exists as to how to control the operation of these discharge valves when a plurality of gas discharge devices are affixed to a vessel and particularly when a plurality of accumulators are provided, each having discharge valves and discharge devices mounted on a plurality of vessels in operative relation an accumulator. A particular example of this problem is found in connection with a railway hopper car. Most railway hopper cars comprise a plurality of hoppers, each of which is unloaded separately.
However, similar problems exist in unloading one or a plurality of static vessels including but not limited to industrial bins.